| Username | Post: Accel DFI problems (Topic#199047) |
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bosv
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| 09-17-08 09:25 AM - Post#1524191
Hi everybody
My first post in this forum. As you can see in the subject I have some Accel DFI problems. First I live in Sweden and as far as I know we are three guys using this system in my country. Not so easy to consult someone.
1. I'm a bit worried about my low vacuum at idle it's around 70 KPa. Do you think I still can use speed density configuration. I have Chevy 454.
2. The second(so far) problem is connection to my laptop When I started tuning I barrowed an old Thoshiba from a freind. But the battery was out and the screen dark. I bought a new Acer Aspire 3100. This have only USB ports no serial. OK I purchased a new communication cable (77994P) which connect to the USB port. This work fine with the old Toshiba but acts strange with my new Acer. I can connect to the ECM but after 1-2 minutes I loose connection. Calmap say 'too many communication errors. ECM now offline'. Anyone seen this before?
This was a long post but it's hard to solve the problem on your own.
/bosv
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Doug_F
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| 09-17-08 09:50 AM - Post#1524205
In response to bosv
I'll comment on #1. If you can scale the MAP scale to give you more resolution there, that MAY be needed and can help.
It also depends a little on what transmission is in your car. Is it a manual or auto. What is the converter? A manual or tight converter may be a little harder to tune than a loose converter.
To me, you can tune a 70 kPa idle without a ton of issue. When you get to 80+ it becomes more of a challenge.
Doug
1972 Nova
6.0L LSx, 80mm BorgWarner, 4L80E
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Danny Cabral
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| 09-17-08 10:17 AM - Post#1524221
In response to bosv
I can connect to the ECM but after 1-2 minutes I loose connection.
Here's a quote from MSD Ignition's support page that sounds like your problem:
One would assume these connection ports would be an easy “plug and play” connection unfortunately they NOT. Some of these adapter cables “USB to 9 pin / RS232” fall short of simply making the connection or keeping the adapter cable “awake”. In some cases if the adapter cable goes to “Sleep” or “hibernates” a complete shut down and restart of the computer is necessary. To date we have found an adapter cable that just simply works and does NOT require any Software or drivers to run it, just plug it in.
The adapter cable is available from “IOGEAR” www.iogear.com part number is GUC232A IOGEAR calls it a “USB to Serial / PDA Converter Cable”.
May God's Grace Bless You
'78 BRONCO: 508' stroker, TFS heads, Dominator MPFI & DIS, A/C, Lentech Strip Terminator AOD, 3:1 Atlas II, modified Dana 44/60-lockers-4.10s, hydroboost/4-disc brakes, ram-assist/heim joint steering, 4' lift, 35' tires |
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bosv
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| 09-17-08 11:36 AM - Post#1524262
In response to Danny Cabral
Thanks for your answers.
#1. I have found the way to scale axis now. Fine you think it is possible to tune with the 70 KPa. Some people over here says it extremly difficult.
I have manual trans. But this problem is connected the other one. It's hard to work when you have to restart the laptop every now and then.
#2 The communication cable have the USB connection.
I don't need the adapter. But as I understand Accel has not rewritten the Calmap SW for USB connection. Instead you have to install sw-driver that handles communication between Calmap and the USB port. But isn't it strange that the old laptop works but not the new one.
/bosv
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Bullshark
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| 09-17-08 11:51 AM - Post#1524273
In response to bosv
What version of Gen VII hardware do you have and what Calmap software version are you running?
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bosv
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| 09-17-08 11:55 AM - Post#1524276
In response to Bullshark
I have ECU firmware V.5.5, Clamap 6.1.1 and Gen7 to USB Port w/ Pro Key 77994P.
The laptop is an Acer Aspire 3100 with Windows XP.
/bosv
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ptest
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| 09-19-08 09:22 PM - Post#1525782
In response to bosv
i started with a dfi gen 7 version 4 ecu. using the serial connection and a usb to serial adapter (keyspan), i was able to make it work. then i decided to 'upgrade' to the latest ecu firmware and 'upgrade' to the latest usb pro key and usb connection. at first, things were fine. then i started getting the ecu disconnected messages. i tried upgrading the usb driver software. no help. i also tried a different laptop. same problem.
i think the problem is with the usb to serial driver on the laptops. if i rebooted the laptop while leaving the ecu on, it would reconnect. anyway, i have returned to the old serial connector with keyspan usb adapter, and it works. so my advice to you is to just go with the keyspan usbto serial adapter. but make sure you use the older keyspan driver - 3.4.0 - the newest one i downloaded from the keyspan website also had the disconnection problem...
as for your low vacuum at idle, i have a 555 cubic inch big block chevy with a big cam. the map at idle is around 70 to 75 kPa. i can get it to idle ok, but i have to use a lot of timing (32 degrees). my ve is also set very low - .220!
good luck!
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weez58
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| 09-20-08 11:39 AM - Post#1526014
In response to ptest
I was told by an Accel EMIC dealer, that the usb key is prone to picking up EMI from the ignition and this causes errors. He said that they stopped using the usb key. Hopefully Accel will eventually come up with a fix for this.
-Bob
| '70 Vette roadster, 383, Dart Pro 1 heads, Ultradyne cam 250d @ .050', Accel Gen 7 EFI, single plane w/port injection, 1200cfm 4 barrel throttle body. |
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bosv
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| 09-20-08 11:45 AM - Post#1526015
In response to ptest
ptest
Before I tried USB adapter I updated to the newest bios and chipset. I also found that it's Polific that makes the USB driver sw. I downloade the latest. After trying with these changes I had the same problems. Then just by some feeling I swiched to another USB port on my laptop.
And it works !!! Now I think there is something wrong with my laptop's port.Now I can start tuning for real. Good to hear that it seems possible to tune with my vacuum. I'll work with the timing.
But I think I have to small injectors 36 lbs/hr.
I plan to switch to 44. What do think of that?
/bosv
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zwede
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| 09-20-08 01:37 PM - Post#1526058
In response to bosv
Yes, 36 lbs/hr sounds small. 42's or 44's would be a better choice unless the engine is very mild. But 70 KPa idle doesn't sound like a mild engine.
| Markus 1971 Vette http://www.corvetteforum.net/c3/zwede |
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ptest
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| 09-20-08 04:18 PM - Post#1526158
In response to zwede
my injectors are 60 lbs/hr, but i think they might be a bit too big for a good idle, since the duty cycle and pulse width are quite low at idle. but the engine makes over 700 hp, so it's a balance between maximum power and good driveablity. i am working on the driveability part right now, making sure it has a good idle, then tuning the tip-in and cruise... i don't think that i would go for more than 60 lbs/hr in injector size...
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bosv
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| 09-20-08 11:36 PM - Post#1526319
In response to ptest
I should of course have described my engine.
It's a chevy 454 LS7 exept cr 11.5. Some work done in the combustion chambers and a little porting. Sinle plane rektangular port manifold. 2 1/8 inch headers. Comp cams 288A-R8 solid roller cam. In a sw dyno pgm the power is estimated 630 hp wich I think is a bit high.
I used this site http://www.rceng.com/technical.aspx
to calculate. It comes up with 47. My 44 could easy be 47 by rising the pressure. How about that idea.
/bosv
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ptest
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| 09-22-08 12:11 AM - Post#1526816
In response to bosv
if you increase your fuel pressure you can effectively increase the flow rate of the injector. in fact, that's why most fuel regulators are connected to the manifold vacuum. i believe the formula for calculating the amount of increase is:
new fuel pressure = (new flow rate/old flow rate)^2 * old fuel pressure
= (47/44)^2 * the fuel pressure the 44's were rated at...
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Danny Cabral
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| 09-22-08 04:09 AM - Post#1526848
In response to ptest
EFI fuel pressure regulators are connected to manifold vacuum to decrease fuel pressure when vacuum exists. They maintain the fuel pressure at a fixed differential above manifold pressure (rather than above just atmospheric pressure). The difference in pressure between the fuel rail and intake manifold or 'pressure differential' across the injector nozzle needs to be maintained so vacuum or boost doesn't adversely manipulate the injector's fuel output.
May God's Grace Bless You
'78 BRONCO: 508' stroker, TFS heads, Dominator MPFI & DIS, A/C, Lentech Strip Terminator AOD, 3:1 Atlas II, modified Dana 44/60-lockers-4.10s, hydroboost/4-disc brakes, ram-assist/heim joint steering, 4' lift, 35' tires |
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bosv
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| 10-01-08 10:26 AM - Post#1533067
In response to ptest
hi ptest
Is it possible for you to share your global setup with me? I think it would be great to compare a working setup with mine.
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ptest
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| 10-02-08 12:22 PM - Post#1533831
In response to bosv
sure. i am not sure how to trade files here though. please let me know how to send the ecm file to you.
also, did you download the latest calmap? it is version 6.1.4 now.
also, there is a file called 'Calmap PNP Calibrations by Application.zip' on the calmap ftp site. it has different calibrations by engine type. it was very educational to look at them. there are two 454 calibrations there. the site is:
http://www.accel-dfi.com/calmap/calmapdownload .asp
i am actually still trying to get a good idle. what i am trying is (and i could be wrong):
- decide what idle to run - i can't seem to get it to idle below around 900 rpm - with 60 lb injectors, the pulse width is 1.7 ms or so, which is close to the lowest limit for controlability?
- so i set the idle to 1000 rpm
- then i am adjusting my ve table to achieve maximum vacuum at that idle speed. this is with the engine fully warmed up (all ve corrections decayed out). no idle spark, and no wide-band adjustment (i set the closed loop ect threshold to a high temperature to disable wide-band).
- once the ve is set, i look at what the air fuel ratio is at that ve, and put that into the air fuel table, so when the wide-band is turned back on, it will have zero error at idle.
- i plan on using a chassis dyno to adjust the ve at other speeds, but in the meantime, will try to drive it around and auto-calibrate using the wide-band...
one thing i noticed when looking at all the calibrations included with calmap is that for acceleration fueling (under fuel/transient in calmap) they use either tps rate of change OR map rate of change to decide how much extra acceleration fuel to add.
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